1. Field of the Invention
The present invention relates to sulfoethyl carbonate- type wetting agents as well as to compositions comprising these carbonates.
2. Related Art
The use of sulfoethyl derivatives of fatty acids is well known in the art, see, for example, U.S. Pat. Nos. 1,881,172; 1,916,776; 3,393,213 and 4,954,282.
Derivatives of this material while having good lathering characteristics and being mild surfactants are nevertheless somewhat hydrolytically unstable. One derivative of this material is a very mild surfactant which is employed in commercial personal washing bars and may also be used in other compositions employing surfactants. The coco derivative of these sulfoethyl compounds, known as sodium cocoyl isethionate or sodium 2-sulfoethyl cocoate is used extensively in personal washing bars. It is believed that one of the reasons for mildness is due to the compounds susceptibility to cleavage by skin esterase enzymes. The cleavage by-products coco fatty acid and sodium isethionate are known to be milder to skin than the active itself. It is theorized that these surfactants could be made even milder by preparing a derivative which, after cleavage, is even more innocuous than, for example, coco fatty acid.
In 1984, Shin Nippon Rika Co., Ltd. in Japanese Patent Application 59-42347 disclosed a detergent composition with one surfactant of the general formula: RO[(C(O)OCH.sub.2 CH.sub.2 O).sub.m (CH.sub.2 Ch.sub.2 O).sub.n ]CH.sub.2 CH.sub.2 SO.sub.3 X where R is an alkyl group, hydroxyalkyl group containing an ether group, with a carbon number of 2-20; X is Li, Na, NH.sub.4 +, or an amine residue; and m+n=2-20. In 1990, Henkel Corp. in European Patent 0,353,503 disclosed a carbonate based surfactant. The structure of the Henkel patent was not based on isethionate.
The compounds developed in the art are not, completely satisfactory.
Accordingly, it is an object of the present invention to provide improved surfactant derivatives which have good lathering capabilities, provide a good critical micelle concentration (CMC), are less sensitive to calcium ion concentration and have good hydrolytic stability.
A further object is to overcome one or more disadvantages of the art.
Other objects of the present invention will become apparent through the following summary, detailed discussion and examples.